The present invention relates to an upper power supply arrangement for use with a mobile vehicular apparatus which includes an aerial platform or cabin and manipulators that are mounted on the distal end of an insulated boom, the aerial platform and the manipulator being completely electrically insulated from each other.
Some mobile vehicles with aerial platforms are used to handle electric cables supported on poles. While electric cables are being processed, it is often required that the electric cables be left "hot", i.e., an electric current flow through the electric cables, in order to prevent an undesirable power failure.
There is known a mobile vehicle with an aerial platform and manipulators which are mounted on the distal end of a boom. The operator who stands on the platform operates on a controller on the platform to actuate the manipulators for processing energized electric cables.
One conventional mobile vehicular apparatus with an aerial platform will be described with reference to FIG. 1 of the accompanying drawings. Actually, FIG. 1 shows a mobile vehicular apparatus with an aerial platform according to the present invention. Since the mobile vehicular apparatus according to the present invention has an appearance or external structure which is the same as that of the conventional mobile vehicular apparatus, the conventional mobile vehicular apparatus will be described with reference to FIG. 1. The mobile vehicular apparatus, generally denoted at 1, comprises an upper assembly including a platform 5 and a manipulator 6 and a lower assembly including a vehicle body 1a. The upper and lower assemblies are electrically insulated from each other by a distal end member 4a of a boom 4, the distal end member 4a being made of a highly electrically insulating material such as FRP (Fiber-Reinforced Plastic) or the like. The manipulator 6 is actuated by a hydraulic actuator which is disposed in the upper assembly and can be actuated by hydraulic pressure that is supplied from the lower assembly. The upper assembly has an electric control system (an upper CPU, etc.) for controlling various devices in the upper assembly, and the lower assembly also has an electric control system (a lower CPU, etc.) for controlling various devices in the lower assembly. Electric signals are transferred between these electric control systems through optical fibers. In this manner, the upper and lower assemblies are operatively connected to each other by hydraulic pressure hoses and an optical fiber cables, and hence are electrically insulated from each other.
Therefore, the electric insulation is sufficiently achieved between the upper and lower assemblies of the mobile vehicular apparatus. As shown in FIG. 4, signals from a master control arm 8 and an upper controller 9 which control the manipulator(slave manipulator arm) 6 are processed by, and control signals are supplied to the manipulator 6 from, an electric control system which includes an upper CPU 81, a servo driver 83, a power supply 84, and an AC/DC converter 85. The electric control system is energized by a single hydraulically operated generator G which is mounted on the platform 5, for example. Accordingly, it is impossible to electrically isolate the platform 5 and the manipulator 6 from each other. The operator M who rides on the platform 5 and operates the manipulator 6 is therefore exposed to dangers under high voltages from energized electric cables. The master control arm 8 is an arm mounted on the platform 5 and manually movable by the operator M. When the master control arm 8 is moved by the operator M, the manipulator 6 is operated, following the motion of the master control arm 8.